Hyperthermia treatment and probe therefor

ABSTRACT

A method of using a probe that emits energy to coagulate lesions is disclosed. The probe is constructed and arranged to emit light from its distal end, either at an angle to its longitudinal axis, or along its longitudinal axis. Optionally, an end reflector may be used to direct the energy in a beam to one side of the fiber end. A reinforcing sleeve for the fiber is mounted to a shielded, Piezo-electric motor constructed and arranged to move the fiber both longitudinally and rotationally within an optional elongate cannula. An MRI system is arranged to generate a series of output signals indicative of temperature in the targeted area. The application of energy is stopped when the temperature at the boundary of the lesion reaches the required hyperthermic temperature. Cooling of the tip portion of the probe is effected by expansion of a supplied cooling fluid through a restrictive orifice into an expansion zone at the probe end. The fiber is encased in a stiff tubular titanium probe with a relatively small fluid supply duct inside the probe with the interior of the probe acting as a return duct for the expanded liquid. The temperature of the probe end is monitored by a sensor in the probe end and controlled by controlling the pressure in the supplied cooling fluid.

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application is a continuation-in-part of U.S. applicationSer. No. 10/014,846 filed on Dec. 14, 2001, which is acontinuation-in-part of PCT/CA01/0095 filed on Jun. 15, 2001, whichclaims priority to U.S. application Ser. No. 09/593,699, filed on Jun.15, 2000, now U.S. Pat. No. 6,418,337, the entireties of which arehereby incorporated by reference.

BACKGROUND OF THE INVENTION

[0002] The treatment of tumors by hyperthermia is known. In one knownprocess, tumors and other lesions to be treated can be heated above apredetermined temperature of the order of 55C so as to coagulate theportion of tissue heated. The temperature range is preferably of theorder of 55 to 65C and does not reach temperatures that can causecarbonization or ablation of the tissue.

[0003] One technique for effecting the heating is to insert into thelesion concerned an optical fiber, which has at its inserted end anelement that redirects laser light from an exterior source in adirection generally at right angles to the length of the fiber. Theenergy from the laser thus extends into the tissue surrounding the endor tip and effects heating. The energy is directed in a beam confined toa relatively shallow angle so that, as the fiber is rotated, the beamalso rotates around the axis of the fiber to effect heating of differentparts of the lesion at positions around the fiber. The fiber can thus bemoved longitudinally and rotated to effect heating of the lesion overthe full volume of the lesion with the intention of heating the lesionto the required temperature without significantly affecting tissuesurrounding the lesion. We define the term “lesion” as used herein tomean any pathologic change in the tissue or organs of a mammaliansubject including, but not limited to, tumors, aortic or otheraneurysms, artery and vein malformations such as thrombosis,hemorrhages, and embolisms.

[0004] At this time the fiber is controlled and manipulated by a surgeonwith little or no guidance apart from the knowledge of the surgeon ofthe anatomy of the patient and the location of the lesion. It isdifficult therefore for the surgeon to effect a controlled heating whichheats the entire lesion while minimizing damage to surrounding tissue.

[0005] It is of course well known that the location of tumors and otherlesions to be excised can be determined by imaging using a magneticresonance imaging system. The imaging system thus generates for thesurgeon a location of the lesion to be excised but there is no systemavailable which allows the surgeon to use the imaging system to controlthe heating effect. In most cases it is necessary to remove the patientfrom the imaging system before the treatment commences and that movementtogether with the partial excision or coagulation of some of the tissuecan significantly change the location of the lesion to be excised thuseliminating any possibility for controlled accuracy.

[0006] It is also known that magnetic resonance imaging systems can beused by modification of the imaging sequences to determine thetemperature of tissue within the image and to determine changes in thattemperature over time.

[0007] U.S. Pat. No. 4,914,608 (LeBiahan) assigned to U.S. Department ofHealth and Human Services issued Apr. 3, 1990 discloses a method fordetermining temperature in tissue.

[0008] U.S. Pat. No. 5,284,144 (Delannoy) also assigned to U.S.Department of Health and Human Services and issued Feb. 8, 1994discloses an apparatus for hyperthermia treatment of cancer in which anexternal non-invasive heating system is mounted within the coil of amagnetic resonance imaging system. The disclosure is speculative andrelates to initial experimentation concerning the viability of MRImeasurement of temperature in conjunction with an external heatingsystem. The disclosure of the patent has not led to a commerciallyviable hyperthermic treatment system.

[0009] U.S. Pat. Nos. 5,368,031 and 5,291,890 assigned to GeneralElectric relate to an MRI controlled heating system in which a pointsource of heat generates a predetermined heat distribution which is thenmonitored to ensure that the actual heat distribution follows thepredicted heat distribution to obtain an overall heating of the area tobe heated. Again this patented arrangement has not led to a commerciallyviable hyperthermia surgical system.

[0010] An earlier U.S. Pat. No. 4,671,254 (Fair) assigned to MemorialHospital for Cancer and Allied Diseases and issued Jun. 9, 1987discloses a method for a non surgical treatment of tumors in which thetumor is subjected to shock waves. This does not use a monitoring systemto monitor and control the effect.

[0011] U.S. Pat. No. 5,823,941 (Shaunnessey) not assigned issued Oct.20, 1998 discloses a specially modified endoscope which designed tosupport an optical fiber which emits light energy and is movedlongitudinally and rotates angularly about its axis to direct theenergy. The device is used for excising tumors and the energy isarranged to be sufficient to effect vaporization of the tissue to beexcised with the gas thus formed being removed by suction through theendoscope. An image of the tumor is obtained by MRI and this is used toprogram a path of movement of the fiber to be taken during theoperation. There is no feedback during the procedure to control themovement and the operation is wholly dependent upon the initialanalysis. This arrangement has not achieved commercial or medicalsuccess.

[0012] U.S. Pat. No. 5,454,807 (Lennox) assigned to Boston ScientificCorporation issued Oct. 3, 1995 discloses a device for use inirradiating a tumor with light energy from an optical fiber in which inconjunction with a cooling fluid which is supplied through a conduitwith the fiber to apply surface cooling and prevent surface damage whileallowing increased levels of energy to be applied to deeper tissues.This arrangement however provides no feedback control of the heatingeffect.

[0013] U.S. Pat. No. 5,785,704 (Bille) assigned to MRC Systems GmbHissued Jul. 28, 1996 discloses a particular arrangement of laser beamand lens for use in irradiation of brain tumors but does not disclosemethods of feedback control of the energy. This arrangement uses highspeed pulsed laser energy for a photo-disruption effect.

[0014] Kahn, et al. in Journal of Computer Assisted Tomography18(4):519-532, July/August 1994; Kahn, et al. in Journal of MagneticResonance Imaging 8: 160-164, 1998; and Vogl, et al. in Radiology 209:381-385, 1998 all disclose a method of application of heat energy from alaser through a fiber to a tumor where the temperature at the peripheryof the tumor is monitored during the application of the energy by MRI.However none of these papers describes an arrangement in which theenergy is controlled by feedback from the monitoring arrangement. Thepaper of Vogl also discloses a cooling system supplied commercially bySomatex of Berlin Germany for cooling the tissues at the probe end. Thesystem is formed by an inner tube through which the fiber passes mountedwithin an outer tube arrangement in which cooling fluid is passedbetween the two tubes and inside the inner tube in a continuous stream.

BRIEF SUMMARY OF THE INVENTION

[0015] It is one object of the present invention, therefore, to providean improved method and apparatus for effecting treatment of a patient byhyperthermia.

[0016] According to a first aspect of the invention there is provided amethod for effecting treatment in a patient comprising:

[0017] Identifying a volume in the patient the whole of which volume isto be heated to a required temperature, the volume being defined by aperipheral surface of the volume;

[0018] providing a heat source and applying heat to the volume withinthe patient by;

[0019] providing the heat source on an invasive probe having alongitudinal axis and an end;

[0020] inserting the end of the probe into the volume;

[0021] arranging the probe to cause directing of heat from the end in adirection at an angle to the longitudinal axis such that a heatingeffect of the probe lies in a disk surrounding the axis;

[0022] arranging the direction of the heat so as to define a heatingzone which forms a limited angular orientation of heating within thedisk such that, as the probe is rotated, the probe causes heating ofdifferent angular segments of the volume within the disk;

[0023] with the probe at a fixed axial position, rotating the probeabout the axis so that the heating zone lies in a selected segment;

[0024] wherein the application of heat by the probe to the selectedsegment causes heat to be transferred from the segment into parts of thevolume outside the segment surrounding the end of the probe;

[0025] and applying cooling to the end of the probe so as to extractheat from the parts surrounding the probe by conduction of heattherefrom.

[0026] Cooling of the probe may be optional. For example, when utilizingfocused ultrasound and e-beam energy, cooling may not be as relevant ormay not be required. With ultrasound energy, fluid may be used as theconduction medium as more specifically describe below. When cooling isused, preferably the amount of cooling to the probe is arranged relativeto the heating such that the parts of the volume surrounding the end ofthe probe are cooled sufficiently to cause a net heating effect by whichsubstantially only the segment of the heating zone is heated to therequired temperature and the parts outside the segment are not heated tothe required temperature. This is preferably arranged so that thecooling maintains the parts outside the segment below a temperaturesufficient to cause coagulation of the tissues therein. Thus when theprobe is rotated to take up a new angle within a new segment, the tissuein the new segment is not in a condition by pre-heating that wouldinterfere with the transmission and diffusion of the heat to thatsegment.

[0027] The arrangement of the present invention, that is the methoddefined above or the method or probe defined hereinafter, can be used ona rigid probe which is intended to be inserted in a straight line into aspecific location in the body of the patient, or can be used on aflexible probe which can be guided in movement through a part of thebody such as a vein or artery to a required location.

[0028] While the most likely and currently most suitable energy sourceis that of laser light, the arrangements described and defined hereincan also be used with other energy sources of the type which can bedirected at an angle from the axis of the probe through which they aresupplied such as electron beams or ultrasound generators.

[0029] In one exemplary arrangement, the above method can be used withMRI real time control of the surgery by which a non-invasive detectionsystem, such as MRI, is operated to generate a series of output signalsover a period of time representative of temperature in the patient asthe temperature of the patient changes during that time. The outputsignals are used to monitor at least one temperature of the volume asthe temperature changes over the period of time. The application of heatto the probe is then controlled in response to the changes intemperature wherein the temperature at the peripheral surface of thevolume is monitored and a measure of the temperature at a location onthe peripheral surface of the volume is used as the determining factoras to when to halt heating by the probe to the location. However thecooling effect can be used without the MRI monitoring to provide anenhanced system in which the whole of the volume required can be heatedto the required temperature.

[0030] In the method in which temperature is monitored, thedetermination as to when to halt heating by the probe to the location ismade based upon the temperature at the peripheral surface of the volume,with the exception that temperatures within the volume may be monitoredto ensure that no serious or dangerous over-temperature occurs withinthe volume due to unexpected or unusual conditions. Thus any suchover-temperature may be detected and used to halt further treatment orto trigger an alarm to the doctor for analysis of the conditions to beundertaken.

[0031] When used as a rigid probe for treatment within a body part suchas the brain or liver, the probe itself may be sufficiently rigid andstrong to accommodate the forces involved and not require the use of acannula or, alternatively, there may be provided a cannula through whichthe probe is inserted, the cannula having an end which is moved to aposition immediately adjacent but outside the volume and the probehaving a rigid end portion projecting from the end of the cannula intothe volume. When used as a non-rigid probe for treatment within a bodypart such as the brain or liver, the probe itself may require the use ofa cannula through which the probe is inserted as described herein.

[0032] In one embodiment of the present invention, the heat sourcecomprises a laser, an optical fiber for communicating light from thelaser and a light-directing element at an end of the fiber for directingthe light from the laser to the predetermined direction relative to thefiber forming the limited angular orientation within the disk.

[0033] In accordance with one embodiment of the present invention whichprovides the necessary level of cooling in a readily controllableprocess, the end of the probe is cooled by liquid-to-liquid,liquid-to-gas and gas-to-gas cooling by:

[0034] providing on the probe a supply duct for a cooling fluidextending from a supply to the end of the probe;

[0035] providing an expansion zone of reduced pressure at the end of theprobe so as to cause the cooling fluid to expand as a gas thusgenerating a cooling effect;

[0036] and providing on the probe a return duct for return of theexpanded gas from the end of the probe.

[0037] In this arrangement, the return duct is preferably of largercross-sectional area than the supply duct and the supply duct includes arestricting orifice at its end where the return duct is larger incross-sectional area by a factor of the order of 200 times larger thanthe orifice of the supply duct.

[0038] Preferably where the probe comprises a tube the supply duct isarranged inside the tube and the return duct is defined by an insidesurface of the tube.

[0039] In this arrangement, the supply duct is attached as tube to aninside surface of the tube and the fiber itself is attached also to theinside.

[0040] In this arrangement, the orifice is provided by a restrictingvalve or neck in the supply duct immediately upstream of the expansionchamber at the end of the probe.

[0041] Where the fiber has a chamfered end of the fiber it may include areflecting coating thereon for directing the light energy to the side.The arrangement of the chamfered end can have the advantage or featurethat the chamfered end is located in the gas rather than being wetted bycooling fluid which can, when there is no coating, interfere with thereflective properties of the coating and thus with the proper controland direction of the light.

[0042] In this arrangement, the chamfered end can be arranged directlyat 45 degrees to provide a light direction lying wholly in a radialplane at right angles to the axis of the fiber. The chamfered end maycarry a coating arranged to reflect light at two different wavelengths.

[0043] In order to accurately control the cooling effect to maintain thenet heating required, there is preferably provided a temperature sensorat the end of the probe, which may be located inside the tube with theconnection therefor passing through the probe to the control systemoutside the probe.

[0044] Preferably the temperature at the end of the probe is controlledby varying the pressure in the fluid as supplied through the supplyduct. This system can allow the temperature to be maintained betweenabout zero and minus 20 degrees Celsius, which provides the requiredlevel of cooling to the probe for the net heating effect.

[0045] According to a second aspect of the invention there is provided amethod for effecting treatment in a patient comprising:

[0046] identifying a volume in the patient to be heated to a requiredtemperature;

[0047] providing a heat source for applying heat to the volume withinthe patient,

[0048] providing a probe mounting the heat source allowing invasiveinsertion of an end of the probe into the patient,

[0049] providing a position control system for moving the end of theprobe to a required position within the patient;

[0050] inserting the end of the probe into the volume;

[0051] providing on the probe a supply duct for a cooling fluidextending from a supply to the end of the probe;

[0052] providing an expansion zone of reduced pressure at the end of theprobe so as to cause the cooling fluid to expand as a gas thusgenerating a cooling effect;

[0053] and providing on the probe a return duct for return of theexpanded gas from the end of the probe.

[0054] According to a third aspect of the invention there is provided aprobe for use in effecting treatment in a patient comprising:

[0055] a heat source for applying heat to a volume within the patient,

[0056] a probe body mounting the heat source thereon for allowinginvasive insertion of an end of the probe into the patient,

[0057] a supply duct on the probe body for a cooling fluid extendingfrom a supply to the end of the probe;

[0058] the probe body being arranged to provide an expansion zone ofreduced pressure at the end of the probe body so as to cause the coolingfluid to expand as a gas thus generating a cooling effect;

[0059] and a return duct on the probe body for return of the expandedgas from the end of the probe.

[0060] According to a fourth embodiment of the present invention thereis provided a method of applying heat to tissue in vivo comprising:

[0061] identifying a quantity of tissue as a target;

[0062] inserting an elongate transmitting medium percutaneously andfeeding said elongate transmitting medium toward said target until adistal end of said elongate transmitting medium is operationallyproximate said target;

[0063] applying energy to said target by sending energy through saidelongate transmitting medium, said energy exiting said distal end andheating said target;

[0064] monitoring said energy application to ensure surroundingnon-targeted tissue is not damaged by heat;

[0065] determining whether the entire targeted area has been heated;

[0066] if necessary, translating said elongate transmitting medium to anunheated area of said target;

[0067] applying energy to said unheated area of said target.

[0068] The step of identifying a quantity of tissue as a target may beaccomplished by analyzing magnetic resonance images and mapping out theextents of a tumor imaged thereby; or by conducting a body contouringanalysis to determine areas of fatty tissue to be removed; or byanalyzing magnetic resonance images to locate a lesion imaged thereby.

[0069] The step of inserting an elongate transmitting mediumpercutaneously and feeding said elongate transmitting medium toward saidtarget until a distal end of said elongate transmitting medium isoperationally proximate said target may be accomplished by:

[0070] determining a safest straight path between the skull and thetarget;

[0071] forming a hole in the skull;

[0072] inserting said elongate transmitting medium through said holetoward said target until said distal end of said elongate transmittingmedium is operationally proximate said target

[0073] Alternatively, the step of inserting an elongate transmittingmedium percutaneously may include the step of inserting a cannula intosaid hole until a distal end of said cannula is operably proximate saidtarget;

[0074] securing the cannula relative the skull;

[0075] and inserting said elongate transmitting medium through saidcannula toward said target until said distal end of said elongatetransmitting medium is operationally proximate said target;

[0076] or by:

[0077] inserting said elongate transmitting medium in an artery;

[0078] feeding said elongate transmitting medium through the arteryuntil a distal end of the elongate transmitting medium is operationallyproximate a lesion or other target;

[0079] or by percutaneously inserting the elongate transmitting mediumproximate an area of fat targeted for heat treatment.

[0080] The step of applying energy to the target through the elongatetransmitting medium may be accomplished by sending light, laser,collimated, or non-collimated, through an optical fiber. Morespecifically, this step may be accomplished by:

[0081] a) causing said energy to exit said distal end at an angle,greater than zero, to a longitudinal axis of the elongate transmittingmedium;

[0082] b) rotating said elongate transmitting medium around saidlongitudinal axis, thereby creating a shaped area of treated tissue;

[0083] c) advancing said elongate transmitting medium;

[0084] d) repeating steps a)-c) until the entire target has been heated.

[0085] Step a) may be accomplished by causing said energy to exit saiddistal end approximately perpendicularly to said longitudinal axis ofthe elongate transmitting medium such that performing step b) results ina shaped area of treated tissue that is disc-shaped; or by causing saidenergy to exit said distal end at an angle other than perpendicular tosaid longitudinal axis of the elongate transmitting medium such thatperforming step b) results in a shaped area of treated tissue that iscone-shaped.

[0086] Alternatively, the step of applying energy to said target bysending energy through said elongate transmitting medium, said energyexiting said distal end and heating said target, may be accomplished byallowing said energy to exit said distal end along a longitudinal axisof the elongate transmitting medium.

[0087] The step of monitoring said energy application to ensuresurrounding non-targeted tissue is not damaged by heat may beaccomplished by taking temperature readings on non-targeted tissueimmediately adjacent said targeted tissue; or by cycling cooling fluidto and from the distal end of the elongate transmitting medium asnecessary to prevent damaging said surrounding non-targeted tissue.

[0088] A fifth embodiment of the present invention provides a method ofdestroying unwanted fat cells comprising:

[0089] a) identifying fat cells to be destroyed thereby defining atarget that is a volume of fat cells;

[0090] b) percutaneously inserting a probe having a distal end capableemitting energy;

[0091] c) positioning said probe such that said distal end isoperationally proximate said target;

[0092] d) emitting energy from the distal end of the probe sufficient todestroy fat cells;

[0093] e) moving the distal end of the probe through the volume of fatcells and emitting energy from the distal end, either successively orsimultaneously, until the targeted volume of fat cells has beendestroyed.

[0094] This method may also include cooling the distal end of the probeto prevent overheating cells that are not included in the volume of fatcells.

[0095] A sixth embodiment of the present invention provides a method ofcoagulating blood in a vascular lesion that includes

[0096] a) identifying a vascular lesion;

[0097] b) percutaneously inserting a probe having a distal end capableemitting energy;

[0098] c) positioning said probe such that said distal end isoperationally proximate said lesion;

[0099] d) emitting energy from the distal end of the probe sufficient tocoagulate said vascular lesion

[0100] wherein said coagulation results in cessation or reduction offlow to said vascular lesion.

[0101] Step b) may include forming an entry hole in the skull of thepatient, fastening a cannula to the entry hole that is constructed andarranged to create an insertion path for a rigid or non-rigid probe thatis aimed directly at the lesion, and inserting the probe into thecannula.

[0102] A seventh embodiment of the present invention provides a methodof repairing, reconstruction or removing tissue comprising:

[0103] a) identifying a target that comprises healthy tissue to berepaired, reconstructed or removed;

[0104] b) percutaneously inserting a probe having a distal end capableemitting energy;

[0105] c) positioning said probe such that said distal end isoperationally proximate said target;

[0106] d) emitting energy from the distal end of the probe sufficient torepair, reconstruct or remove said target;

[0107] e) moving the distal end of the probe through the target tissueand emitting energy from the distal end, either successively orsimultaneously, until the targeted volume has been repaired,reconstructed or removed.

[0108] This method may also include cooling the distal end of the probeto prevent overheating cells that are not included in the targetedtissue.

[0109] The method may also include targeting healthy tissue or targetingscar tissue.

BRIEF DESCRIPTION OF THE DRAWINGS

[0110]FIG. 1 is a schematic illustration of an apparatus for effectingMRI guided laser treatment according to the present invention.

[0111]FIG. 2 is a schematic illustration of the apparatus of FIG. 1 onan enlarged scale and showing the emission of laser energy into thebrain of a patient.

[0112]FIG. 3 is a side elevation of the laser probe of the apparatus ofFIG. 1.

[0113]FIG. 4 is an end elevation of the laser probe of the apparatus ofFIG. 1.

[0114]FIG. 5 is a cross-sectional view of the laser probe and drivemotor therefor of the apparatus of FIG. 1.

[0115]FIG. 6 is an exploded view of the drive motor of the apparatus ofFIG. 1.

[0116]FIG. 7 is a schematic illustration of the shielding of theapparatus of FIG. 1.

[0117]FIG. 8 is a schematic illustration of the effect of the apparatuson a tumor or other lesion to be coagulated.

[0118]FIG. 9 is a longitudinal cross-sectional view through analternative form of a probe that provides a flow of cooling fluid to theend of the probe for cooling the surrounding tissue.

[0119]FIG. 10 is a cross-sectional view along the lines 10-10 of FIG. 9.

[0120]FIG. 11 is a longitudinal cross-sectional view through a furtheralternative form of probe which provides a flow of cooling fluid to theend of the probe for cooling the surrounding tissue.

[0121]FIG. 12 is a cross-sectional view along the lines 12-12 of FIG.11.

[0122]FIG. 13 is a photograph of a cross-section of a tissue sample thathas been heated in three separate segments showing the absence ofheating outside the segments.

DETAILED DESCRIPTION OF THE INVENTION

[0123] In FIG. 1 is shown schematically an apparatus for carrying outMRI controlled laser treatment. The apparatus comprises a magneticresonance imaging system including a magnet 10 provided within ashielded room 11. The magnet 10 can be of any suitable construction andmany different magnet arrangements are available from differentmanufacturers. The magnet includes field coils for generating variationsin the magnetic field which are not shown since these are well known toone skilled in the art together with a radio frequency antenna coilwhich receives signals from the sample in this case indicated as a humanpatient 13.

[0124] The patient 13 rests upon a patient support table 14 on which thepatient is supported and constrained against movement for the operativeprocedure. The fields of the magnet are controlled on an input controlline 15 and the output from the antenna coil is provided on an outputline 16 both of which communicate through a surgeon interface 17 to theconventional MRI control console 18. The MRI console and the magnet areshown only schematically since these are well known to one skilled inthe art and available from a number of different manufacturers.

[0125] The apparatus further includes a laser treatment system includingan optical fiber assembly 20 that transmits heat energy in the form oflight from a laser 21 mounted outside the room 11. The fiber assembly 20extends from the laser 21 to a terminus 36 (FIG. 2), from which theenergy escapes into the relevant part of the patient 13 as discussedhereinafter. The position of the fiber assembly 20 within the patient 13and the orientation of the fiber are controlled by a drive motor 22supported in fixed adjustable position on a stereotaxic frame 23. Themotor communicates through a control line 24 to a device controller 25.In general the device controller 25 receives information from the MRIconsole 18 and from position detectors of the motor 22 and uses thisinformation to control the motor 22 and to operate a power output fromthe laser 21, thereby controlling the position and amount of heat energyapplied to the part within the body of the patient 13.

[0126] In FIG. 2 is shown on a larger scale the patient table 14. Thestereotaxic frame 23 is attached to the table 14 and extends over thehead 26 of the patient 13. The frame 23 is shown schematically andsuitable details will be well known to one skilled in the art, butcarries the motor 22 in a position on the frame 23 through the use of amotor bracket 27. The position of the motor 22 on the frame 23 remainsfixed during the procedure but can be adjusted in the arcuate direction28 around the arch of the frame 23. The frame 23 can also be adjustedforwardly and rearwardly on the table 14. The bracket 27 also allowsrotation of the motor 22 about a point 30 within the frame 23 so thatthe direction of the fiber assembly 20 projecting forwardly from themotor 22 can be changed relative to the frame. 23.

[0127] Referring now to FIG. 3, the basic components of the fiberassembly 20 of the apparatus are shown. The fiber assembly 20 includes arigid cannula 31 surrounding a glass fiber element 35, and arranged toallow sliding and rotational movement of the fiber element 35 within thecannula 31 while holding the fiber element 35 in a direction axial ofthe cannula. 31. The cannula 31 is formed of a suitable rigid MRIcompatible material such as ceramic so that it is stiff and resistant tobending and has sufficient strength to allow the surgeon to insert thecannula 31 into the required location within the body part of thepatient. 13.

[0128] In the arrangement as shown, the apparatus is arranged foroperating upon a tumor 32 (FIG. 2) within the brain 33 of the patient.13. The surgeon therefore creates an opening 34 in the skull of thepatient 13 and directs the cannula 31, in the absence of the rest of thefiber assembly 20, through the opening 34 to the front edge of the tumor32. The cannula 31, once in place, will act as a guide for the remainderof the fiber assembly 20.

[0129] The position of the tumor 32 is determined in an initial set ofMRI experiments using conventional surgical and an analytical techniquesto define the boundaries, that is a closed surface within the volume ofthe brain 33 which constitutes the extremities of the tumor 32. Thesurgical analysis by which the surgeon determines exactly which portionsof the material of the patient 13 should be removed is not a part ofthis invention except to say that conventional surgical techniques areavailable to one skilled in the art to enable an analysis to be carriedout to define the closed surface.

[0130] The angle of insertion of the cannula 31 is selected to bestavoid possible areas of the patient 13 that should not be penetrated,such as major blood vessels, and also so the cannula 31 is pointedtoward a center of the tumor 32.

[0131] The fiber assembly 20 further includes an actual glass fiberelement 35, which has an inlet end (not shown) at the laser 21 and aterminus 36. At the terminus 36 is provided a reflector or prism, whichdirects the laser energy in a beam 37 to one side of the terminus 36.Thus the beam 37 is directed substantially at right angles to the lengthof the fiber and over a small angle around the axis of the fiber. Thebeam 37 forms a cone having a cone angle of the order of 12 to 15degrees. Such fibers are commercially available including the reflectoror prism for directing the light at right angles to the length of thefiber.

[0132] The fiber element 35 is encased to allow the fiber element 35 tobe manipulated in the motor 22. Around the fiber element 35 is a sleeve38 including a first end portion 39 and a longer second portion 40. Theend portion 39 encloses the terminus 36, which is spaced from a tip 41of the end portion 39. The end portion 39 has a length on the order of 7to 11 cm. The second portion 40 is on the order of 48 to 77 cm in lengthand extends from a forward end 141 through to a rear end 42. The firstend portion 39 is formed of a rigid material such as glass. The secondportion 40 is formed of a stiff material which is less brittle thanglass and yet maintains bending and torsional stiffness of the fiberelement 35 so that forces can be applied to the second portion 40 tomove the terminus 36 of the fiber element 35 to a required positionwithin the tumor 32. The second portion 40 is formed of a material suchas fiber reinforced plastics.

[0133] The two portions 39 and 40 are bonded together to form anintegral structure of common or constant diameter selected as a slidingfit through the cannula 31. The first end portion 39 and the cannula 31are sized so that it the first end portion 39 can extend from the distalend of the cannula 31 and reach a distal end of the tumor 32. An averagetumor might have a diameter of the order of 0.5 to 5.0 cm so that theabove length of the forward portion is sufficient to extend through thefull diameter of the tumor 32 while leaving a portion of the order of1.25 cm within the end of the cannula 31. In this way, the substantiallyrigid first end portion 39 remains relatively coaxial with the cannula31.

[0134] The second portion 40 has attached to it a polygonal ornon-circular section 44 and a stop section 45, both of which act asattachment points for rotational and longitudinal sections,respectively. Thus the polygonal section 44 is arranged to co-operatewith a drive member that acts to rotate the second portion 40 andtherefore the fiber element 35. The stop section 45 is arranged toco-operate with a longitudinally movable drive element that moves thesecond portion 40, and therefore the fiber element 35, longitudinally.In this way the terminus 36 can be moved from an initial position, justbeyond the outer end of the cannula 31, outwardly into the body of thetumor 32 until the tip reaches the far end of the tumor 32. In additionthe terminus 36 can be rotated around the axis of the fiber element 35so that heat energy can be applied at selected angles around the axis.By selectively controlling the longitudinal movement and rotation of theterminus 36, therefore, heat energy can be applied throughout acylindrical volume extending from the end of the cannula 31 along theaxis of the cannula 31 away from the end of the cannula. 31. In additionby controlling the amount of heat energy applied at any longitudinalposition and angular orientation, the heat energy can be caused toextend to required depths away from the axis of the cannula 31 so as toeffect heating of the body part of the patient 13 over a selected volumewith the intention of matching the volume of the tumor 32 out to thepredetermined closed surface area defining the boundary of the tumor 32.

[0135] As shown in FIG. 4, the non-circular cross-section of section 44is rectangular with a height greater than the width. However of courseother non-circular shapes can be used provided that the cross-section isconstant along the length of the non-circular section 44 and providedthat the non-circular section 44 can co-operate with a surrounding drivemember to receive rotational driving force therefrom. The stop section45 is generally cylindrical with a top segment 45A removed to assist theoperator in insertion of the fiber into the drive motor.

[0136] Turning now to FIGS. 5 and 6, the drive motor 22 is shown in moredetail for effecting a driving action on the fiber through the sections44 and 45 into the sleeve 38 for driving longitudinal and rotationalmovement of the terminus 36.

[0137] The drive motor comprises a housing 50 formed by an upper half 51and a lower half 52 both of semi-cylindrical shape with the two halvesengaged together to surround the sections 44 and 45 with the sleeve 38extending axially along a center of the housing. 50. At the front 53 ofthe housing 50 is provided a boss defining a bore 54 within which thesleeve 38 forms a sliding fit. This acts to guide the movement of thesleeve at the forward end of the housing.

[0138] Within the housing is provided a first annular mount 55 and asecond annular mount 56 spaced rearwardly from the first. Between thefirst annular mount 55 and the front boss is provided a first encoder 57and behind the second annular mount 56 is provided a second encoder 58.The first annular mount 55 mounts a first rotatable drive disk 59 onbearings 60. The second annular mount carries a second drive disk 61 onbearings 62. Each of the drive disks is of the same shape including agenerally flat disk portion with a cylindrical portion 63 on the rear ofthe disk and lying on a common axis with the disk portion. The bearingsare mounted between a cylindrical inner face of the annular portion 55,56 and an outside surface of the cylindrical portions 63. Each of thedisks is therefore mounted for rotation about the axis of the fiberalong the axis of the housing.

[0139] The disk 59 includes a central plug portion 64, which closes thecenter hole of the disk portion and projects into the cylindricalportion 63. The plug portion has a chamfered or frusto-conical lead insection 65 converging to a drive surface 66 surrounding the section 44and having a common cross-sectional shape therewith. Thus the tipportion 41 of the sleeve 38 can slide along the axis of the housing andengage into the conical lead in section 65 so as to pass through thedrive surface or bore 66 until the section 44 engages into the surface66. In the position, rotation of the disk 59 drives rotation of thesleeve 38 and therefore of the fiber. As the non-circular section 44 hasa constant cross-section, it can slide through the drive surface 66forwardly and rearwardly.

[0140] The disk 61 includes a plug member 67, which engages into thecentral opening in the disk member 61. The plug 67 has an inner surface68, which defines a female screw thread for co-operating with a leadscrew 69. The lead screw 69 has an inner bore 70 surrounding the sleeve38 so that the sleeve 38 is free to rotate and move relative to the bore70. The lead screw 69 also passes through the cylindrical portion 63 ofthe disk 61. Rotation of the disk 61 acts to drive the lead screwlongitudinally along the axes of the housing and the sleeve 38. A rearend 71 of the lead screw is attached to a clamping member 72. Theclamping member 72 includes a first fixed portion 73 attached to therear end 71 of the lead screw and a second loose portion 74 which can beclamped into engaging the fixed portion so as to clamp the end stopmembers 45 in position within the clamping member. The loose portion 74is clamped in place by screws 75. The top segment 45A of the end stop 45engages into a receptacle 76 in the fixed portion 73 so as to orient thesleeve 38 relative to the lead screw.

[0141] The disks 59 and 61 are driven in a ratcheting action by drivemotors 77 and 78 respectively. In an exemplary embodiment the drivemotors are provided by piezoelectric drive elements in which apiezoelectric crystal is caused to oscillate thus actuating areciprocating action that is used to drive by a ratchet process angularrotation of the respective disk.

[0142] The reciprocating action of the piezoelectric crystal 77 and 78is provided by two such motors 77 co-operating with the disk 59 and twomotors 78 co-operating with the disk 61. Each motor is carried on amounting bracket 77A, 78A that is suitably attached to the housing. Theend clamp 72 is generally rectangular in cross-section and slides withina correspondingly rectangular cross-section duct 72A within the housing.Thus the lead screw 69 is held against rotation and is driven axially bythe rotation of the disk 61 while the fiber is free to rotate relativeto the lead screw. The use of a piezoelectric crystal to drive disks isparticularly suitable and provides particular compatibility with the MRIsystem but other drive systems can also be used as set forth previously.

[0143] In other alternative arrangements (not shown), the ratchetingaction can be effected by a longitudinally moveable cable driven fromthe device controller 25 outside the room 11. In a further alternativearrangement, the motor may comprise a hydraulic, or pneumatic motorwhich again effects a ratcheting action by reciprocating movement of apneumatically or hydraulically driven prime mover. Thus selectedrotation of a respective one of the disks can be effected by supplyingsuitable motive power to the respective motor.

[0144] The respective encoder 57, 58 detects the instantaneous positionof the disk and particularly the sleeve portion 63 of the disk, whichprojects into the interior of the encoder. The sleeve portion thereforecarries a suitable element, which allows the encoder to accuratelydetect the angular orientation of the respective disk. In this way theposition of the disks can be controlled by the device controller 25accurately moving the disk 59 to control the angular orientation of thefiber and accurately moving the disk 61 to control the longitudinalposition of the fiber. The longitudinal position is obtained by movingthe lead screw, which carries the end stop 45. The movements areindependent so that the fiber can be rotated while held longitudinallystationary.

[0145] As the motor driving movement of the fiber is used while themagnet and the MRI system is in operation, it is essential that themotor and the associated control elements that are located within theroom 11 are compatible with the MRI system. For this purpose, the powersupply or control cable 24 and the motor must both be free fromferromagnetic components that would be responsive to the magnetic field.In addition it is necessary that the motor 22 and the cable 24 are bothproperly shielded against interference with the small radio frequencysignals that must be detected for the MRI analysis to be effective.

[0146] Referring now to FIG. 7, the room 11 is shielded to prevent radiowaves from penetrating the walls of the room 11 and interfering with theproper operation of the MRI machine 10. Additionally, the cable 24 andthe motor 22 are surrounded by a conductor 80, which extends through anopening 81 in the wall of the room 11. The conductor also passes througha cable port 82 within a wall 83 of the enclosure so that the whole ofthe motor and the cable are encased within the conductor 80.

[0147] In the method of operation, the patient 13 is located on thepatient table and restrained so that the head of the patient 13 remainsmotionless to prevent motion artifacts. The MRI system is then operatedin conventional manner to generate images of the targeted tumor 32. Theimages are used to determine the size and shape of the tumor 32 and todefine the external perimeter 90 of the tumor 32 (FIG. 8). The surgeonalso determines an optimal location to place the cannula 31 so that thecannula 31 is aimed at the targeted tumor 32 without causing damage tosurrounding tissue. Next, the opening 34 is formed in the skull of thepatient 13 and the cannula 31 inserted.

[0148] With the cannula 31 in place, the motor 22 is mounted on theframe 23 and the frame 23 adjusted to locate the motor 22 so that thefiber assembly 20 can be inserted directly into the cannula. 31. Withthe motor 22 properly aligned along the axis of the cannula, 31, thefiber assembly 20 is inserted through the bore of the motor 22 and intothe cannula 31 so as to extend through the cannula 31 until the terminus36 emerges just out of the outer end of the cannula 31. The distance ofthe motor from the cannula 31 can be adjusted so that the terminus 36just reaches the end of the cannula 31 when the lead screw is fullyretracted and the end stop is located in place in the clamp 72.

[0149] With the motor and fiber thus assembled, the MRI system measurestemperatures in the boundary zone 90. The temperature is detected overthe full surface area of the boundary rather than simply at a number ofdiscrete locations. While the measurements are taken, the fiber is movedlongitudinally to commence operation at a first position just inside thevolume of the tumor 32. At a selected angular orientation of the beam,pulses of radiation are emitted by the laser and transmitted into thetumor 32 through the beam 37. The pulses are continued while thetemperature in the boundary layer 90 is detected. As the pulses supplyheat energy into the volume of the tumor 32, the tumor 32 is heatedlocally basically in the segment shaped zone defined by the beam butalso heat is conducted out of the volume of the beam into the remainderof the tumor 32 at a rate dependant upon the characteristics of thetumor 32 itself. Heating at a localized area defined by the beam istherefore continued until the heat at the boundary layer 90 is raised tothe predetermined coagulation temperature on the order of 55 to 65C.Once the boundary layer reaches this temperature, heating at thatsegment shaped zone within the disk is discontinued and the fiber ismoved either longitudinally to another disk or angularly to anothersegment or both to move to the next segment shaped zone of the tumor 32to be heated. It is not necessary to predict the required number ofpulses in advance since the detection of temperature at the boundary isdone in real time and sufficiently quickly to prevent overshoot.However, predictions can be made in some circumstances in order to carryout the application of the heat energy as quickly as possible byapplying high power initially and reducing the power after a period oftime.

[0150] It is desirable to effect heating as quickly as possible so as tominimize the operation duration. Heating rate may be varied by adjustingthe number of pulses per second or the power of the heat source. Care istaken to vary these parameters to match the characteristics of the tumor32, as detected in the initial analysis. Thus the system may vary theenergy pulse rate or power-time history of the heat source to modify thepenetration depth of the heat induced lesion so that it can control theheating zone of an irregularly shaped lesion. The energy applicationrate should not be high enough to result in over heating the tissueoutside of the perimeter of the tumor. The rate of heat application canalso be varied in dependence upon the distance of the boundary from theaxis of the fiber. Thus, the axis of the fiber is indicated at 91 inFIG. 8 and a first distance 92 of the beam to the boundary is relativelyshort at the entry point of the fiber into the tumor 32 and increases toa second larger distance 93 toward the center of the tumor 32. Inaddition to pulses per second, it is also possible to adjust thepower-time history of the laser energy to maximize penetration into thelesion. That is to use high power first for a short period of time andthen ramp the power down throughout the duration of the treatment atthat particular location.

[0151] In some cases it is desirable to maintain the fiber stationary ata first selected longitudinal position and at a first selected angularorientation until the temperature at the boundary reaches the requiredtemperature. In this case the fiber is then rotated through an angleapproximately equal to the beam angle to commence heating at a secondangular orientation with the fiber being rotated to a next angularorientation only when heating at that second orientation is complete. Inthis way heating is effected at each position and then the fiber rotatedto a next orientation position until all angular orientations arecompleted.

[0152] After a first disk shaped portion of the tumor 32 is thus heated,the fiber is moved longitudinally through a distance dependant upon thediameter of the tumor 32 at that location and dependent upon the beamangle so as to ensure the next heated area does not leave unheated tumortissue between the two successive disk shaped areas. Thus the fiber ismoved longitudinally in steps, which may vary in distance depending uponthe diameter and structure of the tumor 32 as determined by the initialanalysis. However the total heating of the tumor 32 is preferablydetermined by the temperature at the boundary without the necessity foranalysis of the temperatures of the tumor 32 inside the boundary or anycalculations of temperature gradients within the tumor 32. When thecomplete boundary of the tumor 32 has been heated to the predeterminedcoagulation temperature, the treatment is complete and the apparatus isdisassembled for removal of the fiber assembly 20 and the cannula 31from the patient 13.

[0153] The system allows direct and accurate control of the heating bycontrolling the temperature at the surface area defined by the boundaryof the tumor 32 so that the whole of the volume of the tumor 32 isproperly heated to the required temperature without heating areasexternal to the tumor 32 beyond the coagulation temperature. In order tomaximize the amount of heat energy which can be applied through thefiber and thereby to effect treatment of larger tumors, it is highlydesirable to effect cooling of the tissue immediately surrounding theend of the fiber so as to avoid overheating that tissue. Overheatingbeyond the coagulation temperature is unacceptable, as it will causecarbonization, which will inhibit further transmission of the heatenergy. Without cooling it is generally necessary to limit the amount ofheat energy that is applied. As energy dissipates within the tissue,such a limitation in the rate of application of energy limits the sizeof the tumor to be treated since dissipation of energy prevents theoutside portions of the tumor from being heated to the requiredcoagulation temperature.

[0154] In FIGS. 9 and 10 is therefore shown a modified laser probe whichcan be used in replacement for the probe previously described, bearingin mind that it is of increased diameter and thus minor modifications tothe dimensions of the structure are necessary to accommodate themodified probe.

[0155] The modified probe 100 comprises a fiber 101 which extends from atip portion 102 including the light dispersion arrangement previouslydescribed to a suitable light source at an opposed end of the fiber aspreviously described. The probe further comprises a support tube 103 inthe form of a multi-lumen extruded plastics catheter for the fiber whichextends along the fiber from an end 104 of the tube just short of thetip 102 through to a position beyond the fiber drive system previouslydescribed. The tube 103 thus includes a cylindrical duct 104 extendingthrough the tube and there are also provided two further ducts 105 and106 parallel to the first duct and arranged within a cylindrical outersurface 107 of the tube.

[0156] The supporting tube 103 has at its end opposite the outer end 104a coupling 108 which is molded onto the end 109 and connects individualsupply tubes 110, 111 and 112 each connected to a respective one of theducts 104, 105 and 106. Multi-lumen catheters of this type arecommercially available and can be extruded from suitable material toprovide the required dimensions and physical characteristics. Thus theduct 104 is dimensioned to closely receive the outside diameter of thefiber so that the fiber can be fed through the duct tube 110 into theduct 104 and can slide through the support tube until the tip 102 isexposed at the end 104.

[0157] While tubing may be available which provides the requireddimensions and rigidity, in many cases, the tubing is however flexibleso that it bends side to side and also will torsionally twist. Thesupport tube is therefore mounted within an optional stiffening tube orsleeve 114, which extends from an end 115 remote from the tip 102 to asecond end 106 adjacent to the tip 102. The end 116 is however spacedrearwardly from the end 104 of the tubing 103, which in turn is spacedfrom the tip 102. The distance from the end 106 to the tip 102 isarranged to be less than a length of the order of 1 inch. The stiffeningtube 114 is formed of a suitable stiff material that isnon-ferro-magnetic so that it is MRI compatible. The support tube 103 isbonded within the stiffening tube 114 so that it cannot rotate withinthe stiffening tube and cannot move side to side within the stiffeningtube. The stiffening tube is preferably manufactured from titanium,ceramic or other material that can accommodate the magnetic fields ofMRI. Titanium generates an artifact within the MRI image. For thisreason the end 116 is spaced as far as possible from the tip 102 SO thatthe artifact is removed from the tip to allow proper imagining of thetissues.

[0158] At the end 116 of the stiffening tube 114 is provided a capsule120 in the form of a sleeve 121 and domed or pointed end 122. The sleevesurrounds the end 116 of the stiffening tube and is bonded thereto so asto provide a sealed enclosure around the exposed part of the tube 103.The capsule 120 is formed of quartz crystal so as to be transparent toallow the escape of the disbursed light energy from the tip 102. Thedistance of the end of the stiffening tube from the tip is arranged suchthat the required length of the capsule does not exceed what can bereasonably manufactured in the transparent material required.

[0159] The tube 111 is connected to a supply 125 of a cooling fluid andthe tube 112 is connected to a return collection 126 for the coolingfluid. Thus, the cooling fluid is pumped through the duct 105 andescapes from the end 104 of the tube 103 into the capsule and then isreturned through the duct 106. The cooling fluid can simply be liquidnitrogen allowed to expand to nitrogen gas at cryogenic temperatures andthen pumped through the duct 105 and returned through the duct 106 whereit can be simply released to atmosphere at the return 126.

[0160] In an alternative arrangement the supply 125 and the return 126form parts of a refrigeration cycle where a suitable coolant iscompressed and condensed at the supply end and is evaporated at thecooling zone at the capsule 120 so as to transfer heat from the tissuesurrounding the capsule 120 to the cooling section at the supply end.

[0161] The arrangement set forth above allows the effective supply ofthe cooling fluid in gaseous or liquid form through the ducts 105 and106 and also effectively supports the fiber 101 so that it is heldagainst side to side or rotational movement relative to the stiffeningtube 114. The location of the tip 102 of the fiber is therefore closelycontrolled relative to the stiffening tube and the stiffening tube isdriven by couplings 130 and 131 shown schematically in FIG. 9 but of thetype described above driven by reciprocating motor arrangements as setforth hereinbefore.

[0162] In FIGS. 11 and 12 is shown the tip section of an alternativeprobe in which cooling of the tip section is effected using expansion ofa gas into an expansion zone. The tip only is shown as the remainder ofthe probe and its movements are substantially as previously described.

[0163] Thus the probe comprises a rigid extruded tube 200 of a suitablematerial, for example titanium, that is compatible with MRI(non-ferromagnetic) and suitable for invasive medical treatment. Afurther smaller cooling fluid supply tube 202 is also separately formedby extrusion and is attached by adhesive to the inside surface of theouter tube. An optical fiber 204 is also attached by adhesive to theinside surface the outer tube so that the fiber is preferablydiametrically opposed to the tube 202.

[0164] The tube 202 is swaged at its end as indicated at 205, whichprojects beyond the end of the tube 201, to form a neck section ofreduced diameter at the immediate end of the tube 202. Thus inmanufacture the extruded tube 201 is cut to length so as to define a tipend 207 at which the outer tube terminates in a radial plane. At the tipend beyond the radial plane, the outer of the inner tube 202 is swagedby a suitable tool so as to form the neck section 205 having an internaldiameter of the order of 0.003 to 0.005 inch.

[0165] The fiber 204 is attached to the tube 201 so that a tip portion208 of the fiber 204 projects beyond the end 207 to a chamfered end face209 of the fiber which is cut at 45 degrees to define a reflective endplane of the fiber.

[0166] The end 207 is covered and encased by a molded quartz end cap 210that includes a sleeve portion 211 closely surrounding the last part ofthe tube 200 and extending beyond the end 207 to an end face 212, whichcloses the capsule. The end face 212 is tapered to define a nose 213,which allows the insertion of the probe to a required location aspreviously described. The end of the tube 201 may be reduced in diameterso that the capsule has an outer diameter matching that of the mainportion of the tube. However in the arrangement shown the capsule isformed on the outer surface so that its outer diameter is larger thanthat of the tube and its inner diameter is equal to the outer diameterof the tube.

[0167] A thermocouple 214 is attached to the inside surface of the outertube 200 at the end 207 and includes connecting wires 215 which extendfrom the thermocouple to the control unit schematically indicated at226. Thus the thermocouple provides a sensor to generate an indicationof the temperature at the end 207 within the quartz capsule. The quartzcapsule is welded to or bonded to the outer surface of the tube asindicated at 215 so as to form a closed expansion chamber within thequartz capsule beyond the end 207. The inner surface 216 of the quartzcapsule is of the same diameter as the outer surface of the tube 200 sothat the expansion chamber beyond the end of the tube 200 has the sameexterior dimension as the tube 200.

[0168] The quartz capsule is transparent so as to allow the reflectedbeam of the laser light from the end face 209 of the fiber to escapethrough the transparent capsule in the limited angular directionsubstantially at right angles to the longitudinal axis of the fiber andwithin the axial plane defined by that longitudinal axis.

[0169] The tube 202 is connected at its end opposite to the tip to afluid supply 219, which forms a pressurized supply of a suitable coolingfluid such as carbon dioxide or nitrous oxide. The fluid supply 219 iscontrolled by the control unit 216 to generate a predetermined pressurewithin the fluid supply to the tube 202 which can be varied so as tovary the flow rate of the fluid through the neck 205. The fluid issupplied at normal or room temperature without cooling. The fluid isnormally a gas at this pressure and temperature but fluids that areliquid can also be used provided that they form a gas at the pressureswithin the expansion chamber and thus go through an adiabatic gasexpansion through the restricted orifice into the expansion chamber toprovide the cooling effect.

[0170] Thus the restricted orifice has a cross-sectional area very muchless than that of the expansion chamber and the return duct provided bythe inside of the tube 201. The items that reduce the effectivecross-sectional area of the return tube 201 are the optical fiber, thesupply tube, two thermocouple wires, the shrink tube that fixes thethermocouple wires to the optical fiber and the adhesives used to bondthe items into place (at the inlet of the discharge duct). Without thearea of the adhesives included in the calculation, the exhaust duct areais about 300 times larger than a delivery orifice diameter of 0.004″(the target size). When considering the area occupied by the adhesives,the exhaust duct inlet area would be approximately 200 to 250 timeslarger than the 0.004″ diameter orifice. Considering the manufacturingtolerance range of the supply tube orifice diameter alone, the exhaustduct area could be anywhere between 190 to 540 times larger than theorifice area (without considering the area occupied by adhesives). It isour estimation that a 200/1 gas expansion will be required to achieveappropriate cooling.

[0171] This allows the gas as it passes into the expansion chamberbeyond the end 205 to expand as a gas thus cooling the quartz capsuleand the interior thereof at the expansion chamber to a temperature inthe range −20C to 0C. This range has been found to be suitable toprovide the required level of cooling to the surface of the quartzcapsule so as to extract heat from the surrounding tissue at a requiredrate. Variations in the temperature in the above range can be achievedby varying the pressure from the supply 219 so that in one example thepressure would be of the order of 700 to 850 psi at a flow rate of theorder of 5 liters per min.

[0172] The tube 202 has an outside diameter of the order of 0.014 inchOD, while the tube 203 has a diameter of the order of 0.079 inch. Thus adischarge duct for the gas from the expansion chamber is defined by theinside surface of the tube 200 having a flow area which is defined bythe area of the tube 200 minus the area taken up by the tube 202 and thefiber 207. This allows discharge of the gas from the expansion chamberdefined within the quartz capsule at a pressure of the order of 50 psiso that the gas can be simply discharged to atmosphere if inert or canbe discharged to an extraction system or can be collected for coolingand returned to the fluid supply 219 if economically desirable. Tipcooling is necessary for optimum tissue penetration of the laser orheating energy, reduction of tissue charring and definition of the shapeof the coagulated zone. The gas expansion used in the present inventionprovides an arrangement that is suitable for higher power densitiesrequired in this device to accommodate the energy supplied by the laserheating system.

[0173] The tip 208 of the fiber 204 is accurately located within theexpansion zone since it is maintained in fixed position within thequartz capsule by its attachment to the inside surface of the outertube. The fiber is located forwardly of the end 207 sufficiently thatthe MRI artifact generated by the end 207 is sufficiently removed fromthe plane of the fiber end to avoid difficulties in monitoring thetemperature within the plane of the fiber end. The outlet orifice of thetube 202 is also located forwardly of the end 207 so as to be locatedwith the cooling effect generated thereby at the plane of the fiber end.

[0174] The end face 209 is located within the expansion chamber 216 sothat it is surrounded by the gas with no liquid within the expansionchamber. Thus, in practice there is no condensate on the end face 209nor any other liquid materials within the expansion chamber that wouldotherwise interfere with the reflective characteristics of the end face209.

[0175] The end face 209 is coated with a reflective coating such as adual dielectric film. This provides a reflection at the two requiredwavelengths of the laser light used as a visible guide beam and as theheat energy source such as He—Ne and Nd:YAG respectively. An alternativecoating is gold, which can alone provide the reflections at the twowavelengths.

[0176] The arrangement of the present invention provides excellent MRIcompatibility both for anatomic imaging as well as MR thermal profiling.Those skilled in the art will appreciate that the cooling system inaccordance with the present invention may also be used withcircumferential fibers having point-of-source energy.

[0177] In operation, the temperature within the expansion zone ismonitored by the sensor 214 so as to maintain that temperature at apredetermined temperature level in relation to the amount of heat energysupplied through the fiber 204. Thus the pressure within the fluidsupply is varied to maintain the temperature at that predetermined setlevel during the hyperthermic process.

[0178] As described previously, the probe is moved to an axial locationwithin the volume to be treated and the probe is rotated in steps so asto turn the heating zone generated by the beam B into each of aplurality of segments within the disk or radial plane surrounding theend face 209. Within each segment of the radial plane, heat energy issupplied by the beam B that is transmitted through the quartz capsuleinto the tissue at that segment. The heat energy is dissipated from thatsegment both by reflection of the light energy into adjacent tissue andby conduction of heat from the heated tissue to surrounding tissue. Asstated previously, those skilled in the art will appreciate that theprobe used with the cooling system in accordance with the presentinvention may include circumferential fibers having point-of-sourceenergy.

[0179] The surface of the capsule is cooled to a temperature so that itacts to extract heat from the surrounding tissue at a rate approximatelyequal to the dissipation or transfer of heat from the segment into thesurrounding tissue. Thus the net result of the heating effect is thatthe segment alone is heated and surrounding tissue not in the segmentrequired to be heated is maintained without any effective heatingthereon, that is no heating to a temperature which causes coagulation orwhich could otherwise interfere with the transmission of heat when itcomes time to heat that tissue in another of the segments. In this waywhen a first segment is heated to the required hyperthermic temperaturethroughout its extent from the probe to the peripheral surface of thevolume, the remaining tissues in the areas surrounding the probe areeffectively unheated so that no charring or coagulation has occurredwhich would otherwise prevent dissipation of heat and in extreme casescompletely prevent penetration of the beam B.

[0180] Thus when each segment in turn has been heated, the probe can berotated to the next segment or to another segment within the same radialplane and further heating can be effected of that segment only.

[0181] In practice in one example, the laser energy can be of the orderof 12 to 15 watts penetrating into a segment having an angle of theorder of 60 to 80 degrees to a depth of the order of 1.5 cm. In order toachieve this penetration without causing heating to the remainingportions of the tissue not in the segment, cooling of the outside of thecapsule to a temperature of the order of minus 5 degrees C. is required.

[0182] In FIG. 13 is shown an actual example of a cross-section oftissue that has been heated in three separate segments marked as sectors1, 2 and 3. The central dark area is where the probe was located beforeit was removed to allow the cross-sectional slice to be taken. Thedarker area that forms approximately 100 degrees opposite sector 2indicates no heating has been applied to that area. The lighter color inthe sectors 1, 2 and 3 indicates coagulation of the tissue. Similarly itwill be noted that the tissue is of the darker color (not heated) in thesmaller areas between sectors 2 and 3 and between sectors 1 and 2. Thusthe cooling effect of the present invention achieves the effect requiredof limiting or prevention heating to the areas outside the selectedsegments.

[0183] The tube 200 is in the example shown above of a rigid structurefor insertion in a straight line as previously described into a specificlocation. The use of a rigid material such as titanium for the outertube avoids the necessity for the cannula 31 previously described andallows the alignment of the probe in its mounting and drive arrangementas previously described to the required location in the patient 13without previously setting up a cannula 31. However other arrangementscan be provided in which the tube 200 is formed of a fully or partialflexible material allowing the tube 200 to bend so as to allow insertionalong suitable passageways such as veins or arteries within the patient13 by using guiding systems well known to one skilled in the art.

[0184] Another exemplary embodiment of the invention provides a methodof using a directed energy beam in conjunction with an MRI machine toheat targeted tissue in a patient. In accordance with the aforementionedteachings, the method can be used, not only to destroy tumors, but anytissue, healthy or otherwise, that has been identified as undesirable.While the apparatus of the present invention has been described asuseable for the identification and destruction of lesions, in particulartumors, the following applications are also considered within the scopeof the present invention.

[0185] A first application pertains to treating patients havinganeurysms and stokes. One object of the present invention is to treataneurysms before the rupture that results in hemorrhagic stroke.Symptoms of aneurysms are found and diagnosis is made during the“pre-event” period prior to stroke. During this period, patients aretypically treated with endovascular coils. Once the aneurysm “pops” andhemorrhagic stroke occurs, the current therapy involves clipping theruptured vessel, usually within three days of the event. The goal is toprevent rebleeding. Both procedures are risky and treatment can be muchmore easily accomplished with the probe and cooling system in accordancewith the present invention.

[0186] Strokes occur when an aneurysm in a blood vessel in the brainruptures, causing brain damage. Aneurysms and ruptured blood vesselshave long been treated using open brain surgery, an extremely riskyprocedure. Recently, a procedure known as coil embolization has gainedpopularity because it obviates the need to open the skull and expose thebrain. Coil embolization involves feeding a catheter into an artery inthe groin and guiding the catheter through the arteries to the affectedsite in the brain. Platinum coils are then sent up through the catheterto the aneurysm, where the coils fill the ballooned area. The coils aredetached and left in the artery permanently, blocking the flow.

[0187] Coil embolization is not free of complications. For example, ifthe aneurysm opening is too wide, allowing the coils to slip out, astent or flexible mesh tube must be inserted across the opening of theartery to hold them in place. Sometimes, surgery is still necessary ifthe aneurysm is not the appropriate shape for embolization. Even withoutcomplications, the procedure requires significant patience and skill tofeed a catheter from the groin into a targeted area of the brain.

[0188] The method of the present invention can be used to treat vascularlesions, such as aneurysms, and strokes and avoid many of thecomplications of coil embolization. Targeting the lesion or rupture isaccomplished in the same manner as locating a tumor. The size andlocation of the targeted lesion or rupture is determined and an optimalplacement for the cannula is chosen. Targeted vessels should be on theorder of 1 mm to 5 mm and are more preferably on the order of 2 mm to 3mm in diameter. A hole is drilled or otherwise formed in the skull andthe cannula is carefully inserted so that the cannula assumes theintended placement. A fiber assembly is inserted through the cannula inthe aforementioned manner until the target is reached. Notably, theexecution of heating the targeted area may be effected using a straightbeam rather than an angled beam if the targeted area is sufficientlysmall. Additionally, the energy source may include non-collimated lightor other form of radiant energy. It may be true that the necessarytemperature to effect the cauterization of the lesion will be lower thanthat needed to terminate tumor tissue. Alternatively, cauterization ofan lesion could be effected, according to the present invention, bythreading a more flexible, yet otherwise structurally similar, catheterthrough an artery in the groin to the targeted site. Obviously, thecatheter, or fiber assembly, would be much longer than that used withthe aforementioned cannula.

[0189] A second alternative application of the present invention isuseful in cosmetic surgery. The field of cosmetic surgery includes manyprocedures that remove excess healthy tissue such as skin, manipulatemuscle tissue and remove fat cells, for example.

[0190] Fat cells are removed using liposuction, a procedure thatinvolves sucking the cells through a small vacuum tube. Liposuction is arelatively violent way of removing cells and often causes damage to thecells immediately surrounding those removed. Predictably, a significantamount of fluid is also sucked through the vacuum probed during theprocedure. Fluid loss is a major concern when performing liposuction.

[0191] The probe, cooling system and method of the present invention canbe used to destroy targeted fat cells by heating the cells with radiantenergy, such as collimated or non-collimated light. The fat cells areheated to a temperature just below the carbonization temperature and theremains are absorbed by the body. No fluid is removed from the body,thereby allowing a more extensive shaping procedure to be performed.Again, this procedure may be performed with a probe having an angledbeam or an axial, point-of-source energy beam.

[0192] The probe, cooling system and method in accordance with thepresent invention may also be used in cosmetic surgical procedures suchas rhytidectomy, which involves the removal and redraping of excess skinand resupporting and tightening underlying muscles and tissues;blepharoplasty, which involves the removal of lax or excess kin on theupper and lower eyelids to minimize sagging; laser resurfacing to removesuperficial scars, age lines and sometimes, precancerous skin lesions;rhinoplasty, which involves the reconstruction and sculpting of the boneand cartilage to reshape the nose; and trauma reconstruction, whichinvolves the repair of facial injuries or deformities from previousinjuries. Other cosmetic surgical procedures involving the removal,repair or reconstruction of tissue are also within the scope of thepresent invention and these procedures may be performed with a probehaving an angled beam or an axial, point-of-source energy beam.

[0193] Since various modifications can be made in my invention as hereinabove described, and many apparently widely different embodiments ofsame made within the spirit and scope of the claims without departingfrom such spirit and scope, it is intended that all matter contained inthe accompanying specification shall be interpreted as illustrative onlyand not in a limiting sense.

What is claimed is:
 1. A method for effecting treatment in a patientcomprising: identifying a volume in the patient the whole of whichvolume is to be heated to a required temperature, the volume beingdefined by a peripheral surface of the volume; providing a heat sourceand applying heat to the volume within the patient by; providing theheat source on an invasive probe having a longitudinal axis and an end;inserting the end of the probe into the volume; arranging the probe tocause directing of heat from the end in a direction at an angle to thelongitudinal axis such that a heating effect of the probe lies in a disksurrounding the axis; arranging the direction of the heat so as todefine a heating zone which forms a limited angular orientation ofheating within the disk such that, as the probe is rotated, the probecauses heating of different angular segments of the volume within thedisk; with the probe at a fixed axial position, rotating the probe aboutthe axis so that the heating zone lies in a selected segment; whereinthe application of heat by the probe to the selected segment causes heatto be transferred from the segment into parts of the volume outside thesegment surrounding the end of the probe; and applying cooling to theend of the probe so as to extract heat from the parts surrounding theprobe by conduction of heat therefrom.
 2. The method according to claim1 including arranging the amount of cooling to the probe relative to theheating such that the parts of the volume surrounding the end of theprobe are cooled sufficiently to cause a net heating effect by whichsubstantially only the segment of the heating zone is heated to therequired temperature and the parts outside the segment are not heated tothe required temperature.
 3. The method according to claim 2 wherein thecooling is arranged to maintain the parts outside the segment below atemperature sufficient to cause coagulation of the tissues therein. 4.The method according to claim 1 including moving the end of the probeaxially within the volume so as to move the disk of the heating effectaxially within the volume from a first disk position to second diskposition.
 5. The method according to claim 1 including the steps of:operating a non-invasive detection system to generate a series of outputsignals over a period of time representative of temperature in thepatient as the temperature of the patient changes during that time;using the output signals to monitor at least one temperature of thevolume as the temperature changes over the period of time; wherein thetemperature at the peripheral surface of the volume is monitored and ameasure of the temperature of the segment at the peripheral surface ofthe volume is used as the determining factor as to when to halt heatingby the probe to the segment.
 6. The method according to claim 1 whereinthe heat source comprises a laser, an optical fiber for communicatinglight from the laser and a light directing element at an end of thefiber for directing the light from the laser to the predetermineddirection relative to the fiber and for forming the limited angularorientation within the disk.
 7. The method according to claim 1 whereinthe end of the probe is cooled by: providing on the probe a supply ductfor a cooling fluid extending from a supply to the end of the probe;providing an expansion zone of reduced pressure at the end of the probeso as to cause the cooling fluid to expand as a gas thus generating acooling effect; and providing on the probe a return duct for return ofthe expanded gas from the end of the probe.
 8. The method according toclaim 7 wherein the temperature of the probe is cooled to a temperaturein the range of about zero to about minus 20 degrees Celsius.
 9. Themethod according to claim 8 wherein the return duct is of largercross-sectional area than the supply duct by a factor of the order of200 to 250 times.
 10. The method according to claim 1 wherein the powerof the heat source is reduced during heating of each segment from aninitial high value to a lower value.
 11. The method according to claim 7wherein the probe comprises an outer tube, wherein the supply duct isarranged inside the outer tube and wherein the return duct is defined byan inside surface of the outer tube.
 12. The method according to claim11 wherein the supply duct is attached to an inside surface of the outertube.
 13. The method according to claim 11 wherein the probe includes aheat energy supply conduit for transporting the heat energy from asupply to the end of the probe and wherein the heat energy supplyconduit is attached to the inside surface of the outer tube.
 14. Themethod according to claim 7 wherein the cooling fluid is a gas which isexpanded through a restricting orifice.
 15. The method according toclaim 14 wherein the supply duct comprises a tube and the restrictingorifice is formed by a reduced necking of the tube at an end thereof atthe expansion zone.
 16. The method according to claim 15 wherein theprobe includes an outer tube and the supply duct is mounted within theouter tube with the end thereof including the necking extending beyondan end of the outer tube.
 17. The method according to claim 9 whereinthe heat source comprises a laser, an optical fiber for communicatinglight from the laser, and a light directing element at an end of thefiber, wherein the light directing element comprises a chamfered end ofthe fiber and wherein the chamfered end is located in the gas in theexpansion zone.
 18. The method according to claim 17 wherein thechamfered end is arranged at 45 degrees.
 19. The method according toclaim 17 wherein the chamfered end carries a coating arranged to reflectlight at two different wavelengths.
 20. The method according to claim 1wherein there is provided a temperature sensor at the end of the probe.21. The method according to claim 12 wherein the probe comprises anouter tube and wherein there is provided a temperature sensor mounted onthe inside surface of the tube at the end of the probe.
 22. The methodaccording to claim 7 wherein the temperature at the end of the probe iscontrolled by varying the pressure in the fluid as supplied through thesupply duct.
 23. A method for effecting treatment in a patientcomprising: identifying a volume in the patient to be heated to arequired temperature; providing a heat source for applying heat to thevolume within the patient; providing a probe mounting the heat sourceallowing invasive insertion of an end of the probe into the patient;providing a position control system for moving the end of the probe to arequired position within the patient; inserting the end of the probeinto the volume; providing on the probe a supply duct for a coolingfluid extending from a supply to the end of the probe; providing anexpansion zone of reduced pressure at the end of the probe so as tocause the cooling fluid to expand as a gas thus generating a coolingeffect; and, providing on the probe a return duct for return of theexpanded gas from the end of the probe.
 24. The method according toclaim 23 wherein the temperature of the probe is cooled to a temperaturein the range of about zero to about minus 20 degrees Celsius.
 25. Themethod according to claim 23 wherein the return duct is of largercross-sectional area than the supply duct.
 26. The method according toclaim 25 wherein the return duct is of the order of 200 to 250 timeslarger than the supply duct.
 27. The method according to claim 23wherein the probe comprises an outer tube, wherein the supply duct isarranged inside the outer tube and wherein the return duct is defined byan inside surface of the outer tube.
 28. The method according to claim27 wherein the supply duct is attached to an inside surface of the outertube.
 29. The method according to claim 27 wherein the probe includes aheat energy supply conduit for transporting the heat energy from asupply to the end of the probe and wherein the heat energy supplyconduit is attached to the inside surface of the outer tube.
 30. Themethod according to claim 23 wherein the cooling fluid is a gas which isexpanded through a restricting orifice.
 31. The method according toclaim 30 wherein the supply duct comprises a tube and the restrictingorifice is formed by a reduced necking of the tube at an end thereof atthe expansion zone.
 32. The method according to claim 31 wherein theprobe includes an outer tube and the supply duct is mounted within theouter tube with the end thereof including the necking extending beyondan end of the outer tube.
 33. The method according to claim 23 whereinthe heat source comprises a laser, an optical fiber for communicatinglight from the laser, and a light directing element at an end of thefiber, wherein the light directing element comprises a chamfered end ofthe fiber and wherein the chamfered end is located in the gas in theexpansion zone.
 34. The method according to claim 33 wherein thechamfered end is arranged at 45 degrees.
 35. The method according toclaim 33 wherein the chamfered end carries a coating arranged to reflectlight at two different wavelengths.
 36. The method according to claim 23wherein there is provided a temperature sensor at the end of the probe.37. The method according to claim 23 wherein the probe comprises anouter tube and wherein there is provided a temperature sensor mounted onthe inside surface of the outer tube at the end of the probe.
 38. Themethod according to claim 23 wherein the temperature at the end of theprobe is controlled by varying the pressure in the cooling fluid assupplied through the supply duct.
 39. The method according to claim 23wherein the heat source comprises a laser and an optical fiber forcommunicating light from the laser to the end of the probe, and whereinthe probe includes an outer tube and a transparent capsule enclosing anend of the outer tube with the fiber extending to a position beyond theend of the tube into the capsule.
 40. A probe for use in effectingtreatment in a patient comprising: a heat source for applying heat to avolume within the patient; a probe body mounting the heat source thereonfor allowing invasive insertion of an end of the probe into the patient;a supply duct on the probe body for a cooling fluid extending from asupply to the end of the probe; the probe body being arranged to providean expansion zone of reduced pressure at the end of the probe body so asto cause the cooling fluid to expand as a gas thus generating a coolingeffect; and, a return duct on the probe body for return of the expandedgas from the end of the probe.
 41. The probe according to claim 40wherein the temperature of the probe is cooled to a temperature in therange of about zero to about minus 20 degrees Celsius.
 42. The probeaccording to claim 40 wherein the return duct is of largercross-sectional area than the supply duct.
 43. The probe according toclaim 42 wherein the return duct is of the order of 200 to 250 timeslarger than the supply duct.
 44. The probe according to claim 40 whereinthe probe body comprises an outer tube, wherein the supply duct isarranged inside the outer tube and wherein the return duct is defined byan inside surface of the outer tube.
 45. The probe according to claim 44wherein the supply duct is attached to an inside surface of the outertube.
 46. The probe according to claim 44 wherein the outer tubeincludes a heat energy supply conduit for transporting the heat energyfrom a supply to the end of the probe and wherein the heat energy supplyconduit is attached to the inside surface of the outer tube.
 47. Theprobe according to claim 40 wherein the cooling fluid is a gas which isexpanded through a restricting orifice.
 48. The probe according to claim47 wherein the supply duct comprises a supply tube and the restrictingorifice is formed by a reduced necking of the supply tube at an endthereof at the expansion zone.
 49. The probe according to claim 40wherein the probe body comprises an outer tube and the supply duct ismounted within the outer tube with the end thereof including the neckingextending beyond an end of the outer tube.
 50. The probe according toclaim 40 wherein the heat source comprises a laser, an optical fiber forcommunicating light from the laser, and a light directing element at anend of the fiber, wherein the light directing element comprises achamfered end of the fiber and wherein the chamfered end is located inthe gas in the expansion zone.
 51. The probe according to claim 50wherein the chamfered end is arranged at 45 degrees.
 52. The probeaccording to claim 50 wherein the chamfered end carries a coatingarranged to reflect light at two different wavelengths.
 54. The probeaccording to claim 40 wherein there is provided a temperature sensor atthe end of the probe.
 55. The probe according to claim 40 wherein theprobe body comprises an outer tube and there is provided a temperaturesensor mounted on the inside surface of the outer tube at the end of theprobe.
 56. The probe according to claim 40 wherein the temperature atthe end of the probe is controlled by varying the pressure in thecooling fluid as supplied through the supply duct.
 57. The probeaccording to claim 40 wherein the heat source comprises a laser and anoptical fiber for communicating light from the laser to the end of theprobe, and wherein the probe includes an outer tube and a transparentcapsule enclosing an end of the outer tube with the fiber extending to aposition beyond the end of the outer tube into the capsule.
 58. A methodof applying heat to tissue in vivo comprising: identifying a quantity oftissue as a target; inserting an elongate transmitting mediumpercutaneously and feeding said elongate transmitting medium toward saidtarget until a distal end of said elongate transmitting medium isoperationally proximate said target; applying energy to said target bysending energy through said elongate transmitting medium, said energyexiting said distal end and heating said target; monitoring said energyapplication to ensure surrounding non-targeted tissue is not damaged byheat; determining whether the entire targeted area has been heated; ifnecessary, translating said elongate transmitting medium to an unheatedarea of said target; applying energy to said unheated area of saidtarget.
 59. The method of claim 58 wherein identifying a quantity oftissue as a target comprises analyzing magnetic resonance images andmapping out the extents of a tumor imaged thereby.
 60. The method ofclaim 58 wherein identifying a quantity of tissue as a target comprisesconducting a body contouring analysis to determine areas of fatty tissueto be removed.
 61. The method of claim 58 wherein identifying a quantityof tissue as a target comprises analyzing magnetic resonance images tolocate an lesion imaged thereby.
 62. The method of claim 58 whereininserting an elongate transmitting medium percutaneously and feedingsaid elongate transmitting medium toward said target until a distal endof said elongate transmitting medium is operationally proximate saidtarget comprises: determining a safest straight path between the skulland the target; forming a hole in the skull; inserting a cannula intosaid hole until a distal end of said cannula is operably proximate saidtarget; securing the cannula relative the skull; inserting said elongatetransmitting medium through said cannula toward said target until saiddistal end of said elongate transmitting medium is operationallyproximate said target.
 63. The method of claim 58 wherein inserting anelongate transmitting medium percutaneously and feeding said elongatetransmitting medium toward said target until a distal end of saidelongate transmitting medium is operationally proximate said targetcomprises: inserting said elongate transmitting medium in an artery;feeding said elongate transmitting medium through the artery until adistal end of the elongate transmitting medium is operationallyproximate a lesion.
 64. The method of claim 58 wherein inserting anelongate transmitting medium percutaneously and feeding said elongatetransmitting medium toward said target until a distal end of saidelongate transmitting medium is operationally proximate said targetcomprises percutaneously inserting the elongate transmitting mediumproximate an area of fat targeted for heat treatment.
 65. The method ofclaim 58 wherein applying energy to said target by sending energythrough said elongate transmitting medium comprises sending lightthrough optical fiber.
 66. The method of claim 65 wherein sending lightthrough optical fiber comprises sending collimated light through opticalfiber.
 67. The method of claim 66 wherein sending collimated lightthrough optical fiber comprises sending laser light through opticalfiber.
 68. The method of claim 58 wherein applying energy to said targetby sending energy through said elongate transmitting medium, said energyexiting said distal end and heating said target comprises: a) causingsaid energy to exit said distal end at an angle, greater than zero, to alongitudinal axis of the elongate transmitting medium; b) rotating saidelongate transmitting medium around said longitudinal axis, therebycreating a shaped area of treated tissue; c) advancing said elongatetransmitting medium; d) repeating steps a)-c) until the entire targethas been heated.
 69. The method of claim 68 wherein step a) comprisescausing said energy to exit said distal end approximatelyperpendicularly to said longitudinal axis of the elongate transmittingmedium such that performing step b) results in a shaped area of treatedtissue that is disc-shaped.
 70. The method of claim 68 wherein step a)comprises causing said energy to exit said distal end at an angle otherthan perpendicular to said longitudinal axis of the elongatetransmitting medium such that performing step b) results in a shapedarea of treated tissue that is cone-shaped.
 71. The method of claim 58wherein applying energy to said target by sending energy through saidelongate transmitting medium, said energy exiting said distal end andheating said target comprises allowing said energy to exit said distalend along a longitudinal axis of the elongate transmitting medium. 72.The method of claim 58 wherein monitoring said energy application toensure surrounding non-targeted tissue is not damaged by heat comprisestaking temperature readings on non-targeted tissue immediately adjacentsaid targeted tissue.
 73. The method of claim 58 wherein monitoring saidenergy application to ensure surrounding non-targeted tissue is notdamaged by heat comprises cycling cooling fluid to and from the distalend of the elongate transmitting medium as necessary to prevent damagingsaid surrounding non-targeted tissue.
 74. A method of destroyingunwanted fat cells comprising: a) identifying fat cells to be destroyedthereby defining a target that is a volume of fat cells; b)percutaneously inserting a probe having a distal end capable emittingenergy; c) positioning said probe such that said distal end isoperationally proximate said target; d) emitting energy from the distalend of the probe sufficient to destroy fat cells; e) moving the distalend of the probe through the volume of fat cells and emitting energyfrom the distal end, either successively or simultaneously, until thetargeted volume of fat cells has been destroyed.
 75. The method of claim74 further comprising cooling the distal end of the probe to preventoverheating cells not included in the volume of fat cells.
 76. A methodof preventing blood from flowing to a lesion, comprising: a) identifyinga lesion; b) percutaneously inserting a probe having a distal endcapable emitting energy; c) positioning said probe such that said distalend is operationally proximate said lesion; d) emitting energy from thedistal end of the probe sufficient to destroy a lumen of a blood vesselleading to said lesion.
 77. The method of claim 76 wherein steps b) andc) comprise: forming an entry hole in the skull of the patient; and,fastening a cannula to the skull through the entry hole, the cannulaconstructed and arranged to create an insertion path for the probe thatis aimed directly at the lesion; inserting the probe into the cannulasuch that said distal end is operationally proximate said lesion.
 78. Amethod of repairing, reconstruction or removing tissue comprising: a)identifying a target that comprises tissue to be repaired, reconstructedor removed; b) percutaneously inserting a probe having a distal endcapable emitting energy; c) positioning said probe such that said distalend is operationally proximate said targeted tissue; d) emitting energyfrom the distal end of the probe sufficient to repair, reconstruct orremove said targeted tissue; e) moving the distal end of the probethrough the targeted tissue and emitting energy from the distal end,either successively or simultaneously, until the targeted volume hasbeen repaired, reconstructed or removed.
 79. The method of claim 77including cooling the distal end of the probe to prevent overheatingtissue that is not included in the targeted tissue.
 80. The method ofclaim 77 wherein the targeted tissue is healthy tissue.
 81. The methodof claim 77 wherein the targeted tissue is scar tissue.